I was just trying to get some Pro's thoughts on, why there would be a shut off valve on the hot line going out of my hot water tank, and no valve on the cold coming in? Is there a reason for this? Is it OK to add a valve on the cold,so I can isolate the tank, by shuting both valves , and would the 3/4 " sweat joints hold under pressure if I want to disconnect and change tanks? I see the same set up a lot at other sites. Thanks for any clues you guys have! Even the shut of on the cold would serve me better! It seems.

Hi Mr. Shove L:

Code requires that a shutoff be installed in the cold water inlet into the water heater so you can do exactly what you suggested... isolate the water heater if needed.

Sometimes we see them on just cold, sometimes both hot and cold and rarely just on the hot water like yours... lucky guy!

I would shut off the main water supply to the house, drain water from the faucets, turn water heater thermostat dial to low temp. and then drain the water heater to at least 6 inches below rim of the heater. Then I would have you install a BALL VALVE...can be sweat or compression type. I have much greater confidence in the sweat type of ball valve... but the compression type work fine and are acceptable... ;)

If you really want to step it up you could install a floodsafe automatic water heater shutoff with sensor (see picture below). This simply cuts into the cold water supply pipe and then gets sweat fit to the pipe. Thereafter, if sensor (placed on floor at low point or inside a water heater pan) senses water it automatically shuts cold water into heater to stop any possible floods... just another thought.

Let me know what you think or if need info. On soldering!

MARK

Thanks a lot Mark. I like your ball valve suggestion, I got it on the work bench ,ready to install tomorrow. Thanks for the confidence,

Glad to help!

Good luck... MARK

Hi Mark what do you think of the sharkbite ball valve or you are against it, Thanks.

John

Quote:

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Originally Posted by Mr Shove L

I was just trying to get some Pro's thoughts on, why there would be a shut off valve on the hot line going out of my hot water tank, and no valve on the cold coming in? Is there a reason for this? Is it OK to add a valve on the cold,so I can isolate the tank, by shuting both valves , and would the 3/4 " sweat joints hold under pressure if I want to disconnect and change tanks? I see the same set up alot at other sites. Thanks for any clues you guys have!! Even the shut of on the cold would serve me better! It seems.

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A cut off valve should never be placed on the inlet side where the cold water enters unless you know that you have a working temperature and pressure relief valve. This valve, in the cold water line would block the water line and stop steam from escaping into the cold water line if you should have a problem where the fire does not shut off and steam accumulates in the water heater tank. And yes I know that most water heaters, if not all have an automatic cut off built into the thermostat. But in a lot of the plumbing industry you try to back up all possible causes for injury or death to the users or workers.

Hi John:

I'm good with the sharkbite fittings threaded into an I.P.S. ball valve like you posted... but not within 18" of the top of the water heater. As a general rule I don't use plastic pipes (pvc or cpvc), pex pipes (viega, wirsbro, zurn) or sharkbite fittings (orings and plastic parts) near the heater as mentioned. If water heater did malfunction or have backdraft condition from gas flue could melt these and cause more issues for owner. If electric, not quite as important, but I generally follow same rules for both gas and electric.

Letmetellu is correct if the cold water shutoff gets closed then yeah... better be a T&P valve (see pictures) in place... course, if no T&P valve in place and excess temp. or excess pressure builds up here's what can happen.. click on this for a show!!

Water Heater Blast!

Click on the low res. video at mid-bottom of the page.

Code requires that the T&P valve be installed during installation and that the pipe be terminated in a non-threaded fitting (pipe ends plain end about 6-12 inches above floor) so people can't just plug this wondeful little device and endanger their families/homes, etc. Of course, code also requires that a shutoff be installed in cold water inlet so not a bad idea to check that the T&P valve was installed...just in case!!...;)

Mr. Shove L:... any concerns... let us know.

MARK

Mrak very good explanation,Thanks.

Regards,
John

Thanks for the reminder !That's a big 10/4 on the T&P valve! And a HOLY _hit on the video.! It's a wonder it don't happen more often (explosion) ,when people get water turned off for non payment? Are T&P is on and working fine... Thanks for help! And I have another question on the water heater , but I'll do it on a new title. Thanks again. Shovel

Thanks for the thumbs up Sumiya!

Mark